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Generation and Assembly of Virus-Specific Nucleocapsids of the Respiratory Syncytial Virus
Published on: July 27, 2021
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Viral evolution identifies a regulatory interface between paramyxovirus polymerase complex and nucleocapsid that
Julien Sourimant1, Vidhi D Thakkar1, Robert M Cox1
1Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA.
Science Advances
|March 18, 2020
Summary
Paramyxovirus replication relies on RNA-dependent RNA polymerase (RdRP) interactions. Compensatory mutations in the nucleocapsid (N) and phosphoprotein (P-XD) regulate RdRP mobility via electrostatic interactions, restoring viral replication.
Area of Science:
- Virology
- Molecular Biology
- Structural Biology
Background:
- Paramyxoviruses are clinically significant negative-polarity RNA viruses.
- The interaction between the RNA-dependent RNA polymerase (RdRP) complex and the viral RNA genome is not well understood.
- Truncated nucleocapsid (N) protein in measles (MeV) and canine distemper (CDV) viruses impairs replication kinetics.
Purpose of the Study:
- To investigate the mechanisms regulating paramyxovirus RNA-dependent RNA polymerase (RdRP) complex function.
- To identify compensatory mutations that restore replication defects in engineered MeV and CDV.
- To elucidate the structural and dynamic interactions governing RdRP activity.
Main Methods:
- Viral evolution approach using recombinant MeV and CDV with defective N protein.
- Minigenome assays to assess RdRP bioactivity.
- Co-affinity precipitation, biolayer interferometry, and molecular docking to analyze protein interactions.
- Analysis of compensatory mutations in N-core and phosphoprotein X domain (P-XD).
Main Results:
- Passaging engineered viruses led to compensatory mutations restoring RdRP bioactivity and replication.
- Mutations clustered in an acidic loop of N-core and a basic face of P-XD.
- An electrostatic-driven interface between N-core and P-XD was identified.
- Compensatory mutations decreased electrostatic compatibility and coprecipitation efficiency, suggesting a regulatory role.
Conclusions:
- Paramyxovirus polymerase mobility is regulated by a molecular checkpoint involving N-core and P-XD interactions.
- Electrostatic interactions between N-core and P-XD modulate the conformational stability of the P-XD assembly.
- Compensatory mutations fine-tune these interactions to restore viral replication.
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